Sleep deprivation in American children is a matter of national concern. Estimates of children with sleep disturbances range from 20% to 40%. Behavior problems, negative mood, neurobehavioral impairments, and academic underachievement have been associated with childhood sleep disturbances. However, significant gaps in this research include longitudinal studies linking sleep disturbances with developmental trajectories of cognitive functioning and mental and physical health problems; tests of physiological systems that operate as mechanisms, increase vulnerability or provide protection against sleep disturbances; and investigations of the ethnic and socioeconomic context within which children often experience sleep disruptions. The objectives of the present study are to: (1) examine linkages between sleep parameters (amount, quality, schedule) and developmental trajectories of mental health, physical health, and cognitive/academic outcomes; (2) investigate multi-system processes, in which associations between sleep disturbances and developmental outcomes are mediated or moderated by vagal tone or vagal suppression; and (3) evaluate the extent to which these associations and developmental processes operate differently by ethnicity, socioeconomic levels, child gender, and pubertal status. The longitudinal design will involve 4 waves of data collection with a one-year lag between each wave. The sample will consist of 320 children (50% girls), 8-10 years of age at T1, with high representation from low SES and African-American families. Sleep parameters will be assessed objectively, via actigraphy, and subjectively, via child and parent reports. Well-established procedures will assess vagal tone and vagal suppression to laboratory challenges. Children's adjustment and health will be assessed with parent, child, and teacher reports. Cognitive skill and achievement will be assessed via standardized tests and grades. The proposed study will advance understanding of child outcomes associated with sleep disturbances (PA-07-140, Research on Sleep and Sleep Disorders), by studying physiological responses that exacerbate or attenuate the effects of sleep disturbances, and by examining public health priorities as outcomes, such as body mass index, physical health and illness, and academic performance (PA-07-046, Research on Mind-Body Interactions and Health). In addition, by utilizing a sample of normally developing children, the proposed study will investigate sleep processes across a wide range of social-ecological risk levels, thereby allowing tests of moderation by risk level and generalization to a broad range of children (PA-07-379, Behavioral and Social Science Research on Understanding and Reducing Health Disparities). Finally, this research will focus on how these processes unfold over time. Findings will illuminate specific forms and timing of sleep disturbances that elevate risk for negative outcomes in childhood, help identify children and families at greatest risk, and shed light on behavioral, physiological, and ecological targets for prevention and intervention. PUBLIC HEALTH RELEVANCE: Sleep disturbances in American children are highly prevalent, and research increasingly demonstrates their harmful effects across multiple domains of child functioning. However, significant gaps in knowledge include longitudinal evidence linking sleep disturbances with developmental trajectories of cognitive functioning and mental and physical health problems; tests of physiological systems that operate as mechanisms, increase vulnerability, or provide protection against sleep disturbances; and investigations of gender- and puberty- related effects, as well as the ethnic and socioeconomic context within which children experience sleep disturbances and associated problems. Findings of the proposed study will illuminate specific forms and timing of sleep disturbances that elevate risk for negative outcomes in childhood, help identify children and families at greatest risk, and shed light on behavioral, physiological, and ecological targets for prevention and intervention.